DRAINAGE SYSTEM FOR MULTI-LAYER EARTH COVER

PROBLEM TO BE SOLVED : To efficiently drain seepage water from a multi-layer earth cover and to improve the drainage efficiency of the multi-layer earth cover. SOLUTION : A sloped seepage water capillary barrier layer composed of a coarse grain layer 18 and a fine grain layer 20 stacked on the upper layer of the layer 18 is formed on the upper surface of earth filling waste, and a plurality of drainage channels 24 are formed in a place where seepage water penetrates into the coarse grain layer 18 by being moved along a gradient by the capillary barrier layer 17. A multi-stage seepage water capillary barrier layer is formed, and a place where the seepage water falls on a coarse grain layer 34 by being moved in the side direction of the gradient by the capillary barrier layer 17 is extended so that the seepage water is discharged downstream.